94 Comments

On page 60 of the High Res version, step number 4, the Z-smooth bar top clamps, the hex head should be on the side of motors, while the rest of the bolt sticks outwards. If one puts in the other way around, it will get in the way of the motors.

Thanks TianChang. It didn’t take all that long really – I found that once I got into the flow I could produce the images pretty quickly because importing the STL files meant that all the hard work (creating the models) was done. What really took too much time was making the belts look acceptable!

Thanks for the suggestion for p60. I had blindly followed the steps and had forgotten that I had to do as you say whilst building mine. I will update the wiki and the document when I next get a chance.

Somemore tips since I just finish a prusa build and it is still fresh in my mind. =D

I may be wrong to, but I had to change out my z-motor coupler bolts too, perhaps down to M3 x 20. I find that with the current lengths, I cannot reach the maximum z-height that the machine is capable of.

And also you might want to include a note to say that “you might not want to secure the z-motors if you have wobbling issues with you x-axis” This is especially true if your threaded rods are not straight. I am at the moment, still trying to rectify that on my build.

I mention about the z-motor coupler bolts because the spinning bolts, if too long, will start scraping against the z-axis smooth bar guides.

And also, you might want to include a warning against tightening the bar clamps too tight. I over-tightened mine and the plastic showed white marks on it. I had one which even cracked but is still doing well. hehe. Maybe we can include some sort of a guide (range of values of something) to the compression on the bar clamps?

Thanks TianChang, These are great tips. I found the same as I was building mine, and so I will incorporate your comments into the documentation when I next get a chance.

I think these notes and tips should definitely go into the wiki – the question is how to make the suggestions (e.g. modifying the Bill of Materials to use M3 x 20 bolts as per your suggestion above) so that it’s clear and without confusing newcomers. Perhaps I will try and contact the original authors and get some ideas.

Found one issue. You instruct to have the x-axis smooth rods flush on the idler side and protruding on the motor side. As a result you have an interference on pg 75: the smooth rod is occupying the same space as the motor. (I don’t have my motors yet, but it appears that this will be a real problem, not just a modeling issue.

I think the rods need to be flush with the motor mount side and there should be no clearance issue on the idler side.

I second TianChang comment. Anyone reading should be careful not to over tighten. most of my clamps are showing stress marks. It’s surprising how little you need to tighten it to make it secure. Go a little bit at a time and check it to see if it moves.

Thanks so much!
This has helped me quite a bit as a newbie. There are a few differences between these instructions and the maker gear Mendel prusa kit. I’m not finished yet, but so far I have found that the J2 dimension is 250 for my kit and the pulleys use smaller bearings than the 608s in the instructions and also the fender washers are not required. I’ll try to keep track of the other differences and post them.

A quick tip for getting the 3rd threaded rod into the vertexes that probably belongs in these instructions- run the inside nut on the first end you put in way up the bar so you can drop the bar through the vertex enough to line the top end up with the other vertexes hole. Otherwise, you might get people trying to force them in on an angle and breaking things.

Hi, in Part 7 Instruction 8 you say to tighten the screws in the idler but not the motor, yet later on in the document you say to shift the rods over as they (may) interfere with the x motor. Wouldn’t it be better to tighten the motor at 7/8 with rods flush with the end of the holes, and let the idler be the adjustable end, since it doesn’t matter if we have rod sticking out the end of the idler?

Hi, I haven’t started building a machine yet, just in research mode now. I must say, these instructions rise to Lego level — if you have ever put together a Lego set, you know what a compliment that is. Bravo!

Hi, Josef asked me a while ago whether I would and I agreed, but so far he hasn’t gotten back to me. I’m not sure whether he wants the instructions to be a part of his Thingidoc, a PDF, or website, etc. Also, I created the first revision as I was building my own Prusa and so it was easy to create the images for each step as they were already written on the wiki.

I have a few general questions to anyone that has built this. I am considering building the Prusa Mendal but I am unsure if my small apartment would work…..or my girlfriend would appreciate a 3D printer in the living room…. How loud is this? same as a regular paper printer or louder? Does it give off fumes? Could this be a fire hazard? or at least smoke detector hazard?

I am trying to weight the pros and cons before I go down this rocky road of 3D printing. If there is anything else I should know that would help.

Hi Jin, If you go the the forums (http://forums.reprap.org) you will see that may people have already asked these questions. I will however say that the printer should be considered a workshop tool not like a paper laser printer for example. That means it is louder than a regular printer and could potentially be a fire hazard (the hot end can get to ~200°C) so care has to be taken. If space is a problem then perhaps consider a huxley or wallace as these are smaller.

For the girlfriend problem, my wife actually thinks reprap looks cool (i got black plastic parts and very shiny smoothrods/threaded rods) so she let me build it in the living room 😀 and now its in our bedroom

These look like awesome instructions on how to build a Prusa Mendal. If you are interested in the technical specs and feedback on the actual 3D printer check out 3D Printing Pad. It also compares the Mendel to all the other 3d printers on the market for household right now.

Hi Gary,
Thanks for the guide! I have a comment.. In part 2, step 1 you refer to the bottom rod (which is a 12″ rod, one out of six of the FRONT-REAR rods..) I mistook that and used the BOTTOM-TOP rods (3 18″ rods) and had to unscrew nuts and bolts for 20 minutes.. Could you update that line to ‘the bottom of two front/rear rods’ in your next revision? Thanks again!

Thanks for the visual guide, it helped a lot being able to look through it before I began ordering all my parts for my reprap prusa mendel build. People like you is what make the reprap 3D community so Incredible.

hi i am from argentina y buy a prusa mendel , but y need mode informacion about programing the printable object , y used the program slicer to configure all that stufs ,
other question sometimes when im printing at half of the printed the object takes of from thje bed , what could it be ?
any informacion you have , manuals etc can send it to my email tomasandresbasile@hotmail.com
thanks

Hello all, I have no 3D printer cause i cant afford it but i have an idea to make this from
other materials, i am looking for a classical technical drawing so i can reproduce all the printable parts of this printer. Does someone knows where i can find that kind of drawings for Prusa ?

Maybe I’m missing something but do your instructions go over the electronics and the actual hot end of the printer? I don’t see a heat bed or resistor or thermister or hot ends included in ur bom.
Please explain
Thank you

Hi
Oh okay, well thank you for that. Its a great guide indeed.
I’m a complete beginner with this stuff and I know nothing about electronics and hotends and etc. Would you kindly suggest any links which can aid me along the way?
Thanks

Hi, There’s a lot of options for hot-ends nowadays so you really have to make your own research, but for what it’s worth I have heard the J-Head is supposed to be quite good (http://hotends.com), and I recently bought a 3mm direct-drive hotend from http://e3d-online.com which appears to be well constructed. I have only just started using it so it’s too early for me to comment on how it prints – though many people are praising them.

This is exactly what I have been looking for to help me get started with this project!! Thanks for putting This togeather.
One question though as I will be ordering the printed parts since this is my first 3D printer… What iteration version is this manual for (or doesnt it matter) Prusa i2 or Prusa i3

I apologize if my question is redundant to this forum, but are you willing/able to print the pieces this manual requires for purchase? I have a great interest in making a 3D printer. These instructions are light years ahead of anything I have found!